SUMMARY
When putting an image in fullscreen in Gwenview, the background color is always set to black, and changing it from 'right click' -> 'background color mode' does not work.
This is particularly annoying for images that have transparent background, or to visualize a photography collection where a clear background allows to better distinguish the colors in the pictures. 

STEPS TO REPRODUCE
1. Open an image with Gwenview
2. Go in fullscreen (CTRL+MAJ+F)
3. Try to change the color mode with 'right click on the image' -> 'background color mode'

OBSERVED RESULT
The color mode does not change.

EXPECTED RESULT
It should change (and IMO it should also follow the theme of the normal view)

SOFTWARE/OS VERSIONS
Operating System: Fedora Linux 41
KDE Plasma Version: 6.3.2
KDE Frameworks Version: 6.11.0
Qt Version: 6.8.2
Kernel Version: 6.13.5-200.fc41.x86_64 (64-bit)
Graphics Platform: Wayland
Graphics Processor: Intel® Iris® Xe Graphics